Enhanced growth of seed viruses for H5N1 influenza vaccines

AbstractSeed viruses used to produce inactivated H5N1 influenza vaccines are recombinant viruses with modified avirulent-type hemagglutinin (HA) and intact neuraminidase (NA) genes, both derived from an H5N1 isolate, and all remaining genes from the PR8 strain, which grows well in eggs. However, some reassortants grow suboptimally in eggs, imposing obstacles to timely, cost-efficient vaccine production. Here, we demonstrate that our PR8 strain supports better in ovo growth than the PR8 strain used for the WHO-recommended seed virus, NIBRG-14. Moreover, inclusion of an alternative NA protein further enhanced viral growth in eggs. These findings suggest that our H5N1 vaccine candidates would increase the availability of H5N1 vaccine doses at the onset of a new pandemic

Effect of Major Diseases on Productivity of a Large Dairy Farm in a Temperate Zone in Japan

The objective of the present study was to investigate the associations between major diseases (clinical mastitis, peracute mastitis, metabolic disorders, peripartum disorders) and four parameters related to productivity (305-day milk yield, number of days open, culling rate, death rate) on a large dairy farm in a temperate zone with approximately 2500 Holstein cows. Data were collected from 2014 to 2018 and involved 9663 calving records for 4256 cows. We found negative effects of clinical mastitis, peracute mastitis, metabolic disorders, and peripartum disorders on the productivity of cows. Clinical-mastitis-suffered cows with multiple diseases had more days open compared with those with clinical mastitis alone and the healthy group, and they had a higher death rate than the healthy group, whereas there was no difference in death rate between the clinical mastitis only and healthy groups. Cows suffering from peracute mastitis, metabolic disorders, and peripartum disorders with either single or multiple diseases exhibited reduced productivity compared with the healthy group. Our findings clearly show that major diseases of cows in a temperate zone have severely negative effects on their productivity

Assessing the pyrogenicity of whole influenza virus particle vaccine in cynomolgus macaques

Among inactivated influenza vaccines, the whole virus particle vaccine (WPV) elicits superior priming responses to split virus vaccine (SV) in efficiently inducing humoral and cellular immunity. However, there is concern for undesired adverse events such as fever for WPV due to its potent immunogenicity. Therefore, this study investigated the febrile response induced by subcutaneous injection with quadriva-lent inactivated influenza vaccines of good manufacturing grade for pharmaceutical or investigational products in cynomolgus macaques. Body temperature was increased by 1 degrees C-2 degrees C for 6-12 h after WPV administration at the first vaccination but not at the second shot, whereas SV did not affect body temperature at both points. Given the potent priming ability of WPV, WPV-induced fever may be attrib-uted to immune responses that uniquely occur during priming. Since WPV-induced fever was blunted by pretreatment with indomethacin (a cyclooxygenase inhibitor), the febrile response by WPV is considered to depend on the increase in prostaglandins synthesized by cyclooxygenase. In addition, WPV, but not SV, induced the elevation of type I interferons and monocyte chemotactic protein 1 in the plasma; these fac-tors may be responsible for pyrogenicity caused by WPV, as they can increase prostaglandins in the brain. Notably, sufficient antibody responses were acquired by half the amount of WPV without causing fever, suggesting that excessive immune responses to trigger the febrile response is not required for acquired immunity induction. Thus, we propose that WPV with a reduced antigen dose should be evaluated for potential clinical usage, especially in naive populations. (c) 2022 The Authors. Published by Elsevier Ltd

Potent priming by inactivated whole influenza virus particle vaccines is linked to viral RNA uptake into antigen presenting cells

Current detergent or ether-disrupted split vaccines (SVs) for influenza do not always induce adequate immune responses, especially in young children. This contrasts with the whole virus particle vaccines (WPVs) originally used against influenza that were immunogenic in both adults and children but were replaced by SV in the 1970s due to concerns with reactogenicity. In this study, we re-evaluated the immunogenicity of WPV and SV, prepared from the same batch of purified influenza virus, in cynomolgus macaques and confirmed that WPV is superior to SV in priming potency. In addition, we compared the ability of WPV and SV to induce innate immune responses, including the maturation of dendritic cells (DCs) in vitro. WPV stimulated greater production of inflammatory cytokines and type-I interferon in immune cells from mice and macaques compared to SV. Since these innate responses are likely triggered by the activation of pattern recognition receptors (PRRs) by viral RNA, the quantity and quality of viral RNA in each vaccine were assessed. Although the quantity of viral RNA was similar in the two vaccines, the amount of viral RNA of a length that can be recognized by PRRs was over 100-fold greater in WPV than in SV. More importantly, 1000-fold more viral RNA was delivered to DCs by WPV than by SV when exposed to preparations containing the same amount of HA protein. Furthermore, WPV induced up regulation of the DC maturation marker CD86 on murine DCs, while SV did not. The present results suggest that the activation of antigen-presenting DCs, by PRR-recognizable viral RNA contained in WPV is responsible for the effective priming potency of WPV observed in naive mice and macaques. WPV is thus recommended as an alternative option for seasonal influenza vaccines, especially for children. (c) 2021 Elsevier Ltd. All rights reserved